DOCSLIB.ORG

Diverse Supraglacial Drainage Patterns on the Devon Ice Cap, Arctic Canada

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Diverse Supraglacial Drainage Patterns on the Devon Ice Cap, Arctic Canada This is a repository copy of Diverse supraglacial drainage patterns on the Devon ice Cap, Arctic Canada. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/166803/ Version: Published Version Article: Lu, Y., Yang, K., Lu, X. et al. (5 more authors) (2020) Diverse supraglacial drainage patterns on the Devon ice Cap, Arctic Canada. Journal of Maps, 16 (2). pp. 834-846. ISSN 1744-5647 https://doi.org/10.1080/17445647.2020.1838353 Reuse This article is distributed under the terms of the Creative Commons Attribution (CC BY) licence. This licence allows you to distribute, remix, tweak, and build upon the work, even commercially, as long as you credit the authors for the original work. More information and the full terms of the licence here: https://creativecommons.org/licenses/ Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. [email protected] https://eprints.whiterose.ac.uk/ Journal of Maps ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/tjom20 Diverse supraglacial drainage patterns on the Devon ice Cap, Arctic Canada Yao Lu , Kang Yang , Xin Lu , Laurence C. Smith , Andrew J. Sole , Stephen J. Livingstone , Xavier Fettweis & Manchun Li To cite this article: Yao Lu , Kang Yang , Xin Lu , Laurence C. Smith , Andrew J. Sole , Stephen J. Livingstone , Xavier Fettweis & Manchun Li (2020) Diverse supraglacial drainage patterns on the Devon ice Cap, Arctic Canada, Journal of Maps, 16:2, 834-846, DOI: 10.1080/17445647.2020.1838353 To link to this article: https://doi.org/10.1080/17445647.2020.1838353 © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of Journal of Maps View supplementary material Published online: 09 Nov 2020. Submit your article to this journal Article views: 135 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tjom20 JOURNAL OF MAPS 2020, VOL. 16, NO. 2, 834–846 https://doi.org/10.1080/17445647.2020.1838353 Science Diverse supraglacial drainage patterns on the Devon ice Cap, Arctic Canada Yao Lu a, Kang Yang a,b,c, Xin Lu a, Laurence C. Smithd,e, Andrew J. Sole f, Stephen J. Livingstone f, Xavier Fettweisg and Manchun Lia,b aSchool of Geography and Ocean Science, Nanjing University, Nanjing, People’s Republic of China; bJiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Nanjing, People’s Republic of China; c Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, People’s Republic of China; dInstitute at Brown for Environment and Society, Brown University, Providence, RI, USA; eDepartment of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, USA; fDepartment of Geography, University of Sheffield, Sheffield, UK; gDepartment of Geography, University of Liège, Liège, Belgium ABSTRACT ARTICLE HISTORY The Devon Ice Cap (DIC) is one of the largest ice masses in the Canadian Arctic. Each summer, Received 30 August 2019 extensive supraglacial river networks develop on the DIC surface and route large volumes of Revised 2 June 2020 meltwater from ice caps to the ocean. Mapping their extent and understanding their Accepted 14 October 2020 ff temporal evolution are important for validating runo routing and melt volumes predicted KEYWORDS by regional climate models (RCMs). We use 10 m Sentinel-2 images captured on 28 July and 2 Supraglacial rivers; regional 10/11 August 2016 to map supraglacial rivers across the entire DIC (12,100 km ). Both climate model (RCM); dendritic and parallel supraglacial drainage patterns are found, with a total length of Sentinel-2; Devon ice Cap; −1 44,941 km and a mean drainage density (Dd) of 3.71 km . As the melt season progresses, Arctic Dd increases and supraglacial rivers form at progressively higher elevations. There is a positive correlation between RCM-derived surface runoff and satellite-mapped Dd, suggesting that supraglacial drainage density is primarily controlled by surface runoff. 1. Introduction large volumes of surface meltwater are transferred to The Arctic contains numerous large ice masses includ- the ice bed, influencing the evolution of subglacial ing the Greenland Ice Sheet, Devon Ice Cap (DIC) and hydrological systems and ice flow dynamics (Chu, Agassiz Ice Cap, with a total collective area of approxi- 2014; Iken & Bindschadler, 1986; Pitcher & Smith, mately two million square kilometers (Abdalati et al., 2019; Röthlisberger & Iken, 1981; Schoof, 2010; Sundal 2004; Cook et al., 2019; Gardner et al., 2011). The Arc- et al., 2011). Although the spatial structure of these tic is also highly sensitive to global climate change supraglacial river networks is thought to be controlled (Screen & Simmonds, 2010), and is currently warming by the surface topography (Yang et al., 2015a) through at roughly twice the global average rate, with annual the transfer of bed variability to the ice surface at the air temperatures for October 2015 to September large scale (Crozier et al., 2018; Ignéczi et al., 2018), 2016 averaging +2.0°C warmer than the 1981–2010 their temporal evolution is affected by the rate and average (Richter-Menge et al., 2016). Associated magnitude of meltwater production and the per- mass loss from Arctic ice masses contributed ∼31% meability of glacier surface throughout the melt season of observed global sea level rise between 1992 and (Irvine-Fynn et al., 2011; Lampkin & Vanderberg, 2017 (Box et al., 2018), with annual ice mass losses 2014). − averaging 50.2 Gt a 1 in the Canadian Arctic, over In general, large supraglacial river networks have twice the pre-1996 average (Noël et al., 2018). It is only recently begun attracting scientific attention therefore essential to understand factors that affect with most studies focused on the Greenland Ice the prevalence, spatial pattern, and transport of sur- Sheet (Colgan et al., 2011; Crozier et al., 2018; Gleason face meltwater from Arctic ice masses to oceans. et al., 2016; Ignéczi et al., 2018; King et al., 2016; During 2016, the warmest year in the Arctic since Lampkin & Vanderberg, 2014; Legleiter et al., 2014; 1900 (Richter-Menge et al., 2016), Arctic ice masses Pitcher & Smith, 2019; Poinar et al., 2015; Smith experienced significant surface melt, which formed et al., 2015; Smith et al., 2017; Yang & Smith, 2016). large and complex supraglacial river networks at Yang et al. (2019a) mapped small areas of the Devon their lower elevations in summer (Pitcher & Smith, and Barnes Ice Caps (as well as the northwest Green- 2019). Where supraglacial rivers terminate in moulins, land Ice Sheet) using 10 m Sentinel-2 visible/near- CONTACT Kang Yang [email protected] School of Geography and Ocean Science, Nanjing University, Nanjing, People’s Republic of China; Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Nanjing, People’s Republic of China; University Corporation for Polar Research, Beijing, People’s Republic of China Supplemental data for this article can be accessed https://doi.org/10.1080/17445647.2020.1838353 © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of Journal of Maps This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrest- ricted use, distribution, and reproduction in any medium, provided the original work is properly cited. JOURNAL OF MAPS 835 infrared satellite images and found that the drainage patterns and densities of supraglacial river networks may differ significantly within and between different ice masses. Previous studies have documented supraglacial river formation on the DIC (Fernandes et al., 2018; Wyatt, 2013; Wyatt & Sharp, 2015; Yang et al., 2019a). Wyatt (2013) manually digitized supraglacial rivers across the DIC from Landsat 7 ETM+ imagery acquired during the 1999 summer, revealing that both surface topography and ice dynamics affect supraglacial drai- nage patterns. Yang et al. (2019a) mapped a snapshot of supraglacial rivers on the western and southern DIC, demonstrating the strong potential of 10 m Senti- nel-2 imagery to investigate supraglacial drainage pat- terns. However, the spatial distribution, drainage patterns and seasonal evolution of supraglacial rivers across the entire DIC and how their formation is Figure 1. Location of the Devon Ice Cap in the Canadian affected by surface runoff remain poorly understood. Arctic. Here, we build upon the preliminary study of Yang et al. (2019a) using Sentinel-2 satellite images to map from 2005–2009 than from 1963–2005 (Sharp et al., supraglacial river networks and drainage across the 2011). entire DIC, their mid- to late-season evolution, and The main ice cap has a dome-like shape with a ff response to surface runo . First, we extract the supra- maximum elevation of 1921m (Dowdeswell et al., glacial rivers from satellite images by integrating 2004). Eight major drainage basins (471–2,623 km2), cross-sectional and longitudinal open-channel mor- obtained from the Randolph Glacier Inventory 6.0 phometry. Then, we calculate the supraglacial drai- (RGI Consortium, 2017), cover 78% of the total area ff nage density within di erent elevation bands and of DIC (Figure 2)(Table 2). There are strong spatial drainage
Load more

Recommended publications
  • N National Museum of Natural History June 2002 Number 10
    ewsletterewsletter Smithsonian Institution NN National Museum of Natural History June 2002www.mnh.si.edu/arctic Number 10 NOTES FROM THE DIRECTOR for the University of Maryland. Irwin Shapiro, Director of By Bill Fitzhugh the Smithsonian Astrophysical Observatory, has been named Interim Under Secretary; and Douglas Erwin has been named In thirty two years at the Smithsonian, I have never Interim Director of NMNH while the search for a permanent experienced a year quite like the last one. In the past, the person for both positions continues. Yours Truly has become Smithsonian seemed immune from worldly upheavals, and Chair of Anthropology (a post I held from 1975-80). By this sailed steadily forward even in troubled times. During these time next year the Science Commission Report will have been years, the Institution changed physically and intellectually, on the table for six months, and I hope to report new directions increased the social and ethnic diversity of its staff and and improved prospects for Smithsonian science. programming, and began to diversify its funding stream; but the basic commitment to scholarship and research remained solid. *** Today, this foundation is being challenged as never before. The result has been an unusual year, to say the least. A Despite difficult times, the ASC has maintained its core stream of directors—seven or eight at last count—have left programs and has initiated new projects. At long last, Igor their posts; a special commission has investigated American Krupnik and I, with assistance from Elisabeth Ward, History’s exhibition program; a congressional science succeeded in realizing the dream of a dedicated ASC monograph commission is evaluating Smithsonian science; and two series.
    [Show full text]
  • High Arctic Holocene Temperature Record from the Agassiz Ice Cap and Greenland Ice Sheet Evolution
    High Arctic Holocene temperature record from the Agassiz ice cap and Greenland ice sheet evolution Benoit S. Lecavaliera,1, David A. Fisherb, Glenn A. Milneb, Bo M. Vintherc, Lev Tarasova, Philippe Huybrechtsd, Denis Lacellee, Brittany Maine, James Zhengf, Jocelyne Bourgeoisg, and Arthur S. Dykeh,i aDepartment of Physics and Physical Oceanography, Memorial University, St. John’s, Canada, A1B 3X7; bDepartment of Earth and Environmental Sciences, University of Ottawa, Ottawa, Canada, K1N 6N5; cCentre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark, 2100; dEarth System Science and Departement Geografie, Vrije Universiteit Brussel, Brussels, Belgium, 1050; eDepartment of Geography, University of Ottawa, Ottawa, Canada, K1N 6N5; fGeological Survey of Canada, Natural Resources Canada, Ottawa, Canada, K1A 0E8; gConsorminex Inc., Gatineau, Canada, J8R 3Y3; hDepartment of Earth Sciences, Dalhousie University, Halifax, Canada, B3H 4R2; and iDepartment of Anthropology, McGill University, Montreal, Canada, H3A 2T7 Edited by Jeffrey P. Severinghaus, Scripps Institution of Oceanography, La Jolla, CA, and approved April 18, 2017 (received for review October 2, 2016) We present a revised and extended high Arctic air temperature leading the authors to adopt a spatially homogeneous change in reconstruction from a single proxy that spans the past ∼12,000 y air temperature across the region spanned by these two ice caps. 18 (up to 2009 CE). Our reconstruction from the Agassiz ice cap (Elles- By removing the temperature signal from the δ O record of mere Island, Canada) indicates an earlier and warmer Holocene other Greenland ice cores (Fig. 1A), the residual was used to thermal maximum with early Holocene temperatures that are estimate altitude changes of the ice surface through time.
    [Show full text]
  • PALEOLIMNOLOGICAL SURVEY of COMBUSTION PARTICLES from LAKES and PONDS in the EASTERN ARCTIC, NUNAVUT, CANADA an Exploratory Clas
    A PALEOLIMNOLOGICAL SURVEY OF COMBUSTION PARTICLES FROM LAKES AND PONDS IN THE EASTERN ARCTIC, NUNAVUT, CANADA An Exploratory Classification, Inventory and Interpretation at Selected Sites NANCY COLLEEN DOUBLEDAY A thesis submitted to the Department of Biology in conformity with the requirements for the degree of Doctor of Philosophy Queen's University Kingston, Ontario, Canada December 1999 Copyright@ Nancy C. Doubleday, 1999 National Library Bibliothèque nationale 1*1 of Canada du Canada Acquisitions and Acquisitions et Bibf iographic Services services bibliographiques 395 Wellington Street 395. rue Wellington Ottawa ON KIA ON4 Ottawa ON K1A ON4 Canada Canada Your lYe Vorre réfhœ Our file Notre refdretua The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive pemettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, Ioan, distribute or sell reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/nlm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or othemise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son pemission. autorisation. ABSTRACT Recently international attention has been directed to investigation of anthropogenic contaminants in various biotic and abiotic components of arctic ecosystems. Combustion of coai, biomass (charcoal), petroleum and waste play an important role in industrial emissions, and are associated with most hurnan activities.
    [Show full text]
  • Glacial Morphology of the Cary Age Deposits in a Portion of Central Iowa John David Foster Iowa State University
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1-1-1969 Glacial morphology of the Cary age deposits in a portion of central Iowa John David Foster Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Recommended Citation Foster, John David, "Glacial morphology of the Cary age deposits in a portion of central Iowa" (1969). Retrospective Theses and Dissertations. 17570. https://lib.dr.iastate.edu/rtd/17570 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. GLACIAL MORPHOLOGY OF THE CARY AGE DEPOSITS IN A PORTION OF CENTRAL IOWA by John David Foster A Thesis Submitted to the . • Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of MASTER OF SCIENCE Major Subject: Geology Approved: Signatures have been redacted for privacy rs ity Ames, Iowa 1969 !/Y-J ii &EW TABLE OF CONTENTS Page ABSTRACT vii INTRODUCTION Location 2 Drainage 3 Geologic Description 3 Preglacial Topography 6 Pleistocene Stratigraphy 12 Acknowledgments . 16 GLACIAL GEOLOGY 18 General Description 18 Glacial Geology of the Study Area 18 Till Petrofabric Investigation 72 DISCUSSION 82 Introduction 82 Hypothetical Regime of the Cary Glacier 82 Review
    [Show full text]
  • Cryosat-2 Delivers Monthly and Inter-Annual Surface Elevation Change for Arctic Ice Caps
    The Cryosphere, 9, 1895–1913, 2015 www.the-cryosphere.net/9/1895/2015/ doi:10.5194/tc-9-1895-2015 © Author(s) 2015. CC Attribution 3.0 License. CryoSat-2 delivers monthly and inter-annual surface elevation change for Arctic ice caps L. Gray1, D. Burgess2, L. Copland1, M. N. Demuth2, T. Dunse3, K. Langley3, and T. V. Schuler3 1Department of Geography, University of Ottawa, Ottawa, K1N 6N5, Canada 2Natural Resources Canada, Ottawa, Canada 3Department of Geosciences, University of Oslo, Oslo, Norway Correspondence to: L. Gray ([email protected]) Received: 29 April 2015 – Published in The Cryosphere Discuss.: 26 May 2015 Revised: 15 August 2015 – Accepted: 3 September 2015 – Published: 25 September 2015 Abstract. We show that the CryoSat-2 radar altimeter can 1 Introduction provide useful estimates of surface elevation change on a variety of Arctic ice caps, on both monthly and yearly Recent evidence suggests that mass losses from ice caps and timescales. Changing conditions, however, can lead to a glaciers will contribute significantly to sea level rise in the varying bias between the elevation estimated from the radar coming decades (Meier et al., 2007; Gardner et al., 2013; altimeter and the physical surface due to changes in the ratio Vaughan et al., 2013). However, techniques to measure the of subsurface to surface backscatter. Under melting condi- changes of smaller ice caps are very limited: Satellite tech- tions the radar returns are predominantly from the surface so niques, such as repeat gravimetry from GRACE (Gravity Re- that if surface melt is extensive across the ice cap estimates covery and Climate Experiment), favour the large Greenland of summer elevation loss can be made with the frequent or Antarctic Ice Sheets, while ground and airborne exper- coverage provided by CryoSat-2.
    [Show full text]
  • A Descriptiol\ of the PENNY ICE CAP. ITS Accuml: LATION and ABLATION
    342 JOURNAL OF GLACIOLOGY STUDIES IN GLACIER PHYSICS ON THE PENNY ICE CAP, BAFFIN ISLAND, I953 INTRODUCTION Studies in glacier physics formed a major part of the work of the Baffin Island Expedition, 1953, the second expedition of the Arctic Institute of North America to Baffin. This work will be reported in a series of articles in this journal: the first (Part I) appears below; further parts will follow in due course. It was decided to visit the Penny Ice Cap of the Cumberland Peninsula as a sequel to our work on the Barnes Tee Cap in 1950, since it is the only other large area of glaciation in Baffin Island and because our knowledge of the glaciation of the eastern Canadian Arctic is still very limited. From a study of the aerial photographs taken by the Roya l Canadian Air Force in 1948 and the map, together with a consideration of the general resources of the expedition, it was planned to land a glacio-meteorological camp (Camp AI) by means of a Norseman aircraft on a high dome of the ice cap and another camp in the region of the firn line of onc of the more accessible glaciers (now called Highway Glacier) flowing into the head of the Pangnirtung Pass (see Figs. I and 3, pp. 343 and 347). Here there are two lakes, which were considered to be suitable for spring and autumn aircraft landings and for a base camp. From the two glacier camps it was planned to assess the particular regimen of the glaciation and to couple with this studies of some more general problems in glacier physics.
    [Show full text]
  • Supraglacial Rivers on the Northwest Greenland Ice Sheet, Devon Ice Cap, and Barnes Ice Cap Mapped Using Sentinel-2 Imagery
    This is a repository copy of Supraglacial rivers on the northwest Greenland Ice Sheet, Devon Ice Cap, and Barnes Ice Cap mapped using Sentinel-2 imagery. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/141238/ Version: Accepted Version Article: Yang, K., Smith, L., Sole, A. et al. (4 more authors) (2019) Supraglacial rivers on the northwest Greenland Ice Sheet, Devon Ice Cap, and Barnes Ice Cap mapped using Sentinel-2 imagery. International Journal of Applied Earth Observation and Geoinformation, 78. pp. 1-13. ISSN 0303-2434 https://doi.org/10.1016/j.jag.2019.01.008 Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/). Reuse This article is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs (CC BY-NC-ND) licence. This licence only allows you to download this work and share it with others as long as you credit the authors, but you can’t change the article in any way or use it commercially. More information and the full terms of the licence here: https://creativecommons.org/licenses/ Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. [email protected] https://eprints.whiterose.ac.uk/ 1 Supraglacial rivers on the northwest Greenland Ice Sheet, Devon Ice Cap, and 2 Barnes Ice Cap mapped using Sentinel-2 imagery 3 Kang Yang1,2,3, Laurence C.
    [Show full text]
  • Changes in Glacier Facies Zonation on Devon Ice Cap, Nunavut, Detected
    The Cryosphere Discuss., https://doi.org/10.5194/tc-2018-250 Manuscript under review for journal The Cryosphere Discussion started: 26 November 2018 c Author(s) 2018. CC BY 4.0 License. 1 Changes in glacier facies zonation on Devon Ice Cap, Nunavut, detected from SAR imagery 2 and field observations 3 4 Tyler de Jong1, Luke Copland1, David Burgess2 5 1 Department of Geography, Environment and Geomatics, University of Ottawa, Ottawa, Ontario 6 K1N 6N5, Canada 7 2 Natural Resources Canada, 601 Booth St., Ottawa, Ontario K1A 0E8, Canada 8 9 Abstract 10 Envisat ASAR WS images, verified against mass balance, ice core, ground-penetrating radar and 11 air temperature measurements, are used to map changes in the distribution of glacier facies zones 12 across Devon Ice Cap between 2004 and 2011. Glacier ice, saturation/percolation and pseudo dry 13 snow zones are readily distinguishable in the satellite imagery, and the superimposed ice zone can 14 be mapped after comparison with ground measurements. Over the study period there has been a 15 clear upglacier migration of glacier facies, resulting in regions close to the firn line switching from 16 being part of the accumulation area with high backscatter to being part of the ablation area with 17 relatively low backscatter. This has coincided with a rapid increase in positive degree days near 18 the ice cap summit, and an increase in the glacier ice zone from 71% of the ice cap in 2005 to 92% 19 of the ice cap in 2011. This has significant implications for the area of the ice cap subject to 20 meltwater runoff.
    [Show full text]
  • Ice Velocity Changes on Penny Ice Cap, Baffin Island, Since the 1950S
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Crossref Journal of Glaciology (2017), 63(240) 716–730 doi: 10.1017/jog.2017.40 © The Author(s) 2017. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons. org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Ice velocity changes on Penny Ice Cap, Baffin Island, since the 1950s NICOLE SCHAFFER,1,2 LUKE COPLAND,1 CHRISTIAN ZDANOWICZ3 1Department of Geography, Environment and Geomatics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada 2Natural Resources Canada, Geological Survey of Canada, 601 Booth St., Ottawa, Ontario K1A 0E8, Canada 3Department of Earth Sciences, Uppsala University, Uppsala 75236, Sweden Correspondence: Nicole Schaffer <[email protected]> ABSTRACT. Predicting the velocity response of glaciers to increased surface melt is a major topic of ongoing research with significant implications for accurate sea-level rise forecasting. In this study we use optical and radar satellite imagery as well as comparisons with historical ground measurements to produce a multi-decadal record of ice velocity variations on Penny Ice Cap, Baffin Island. Over the period 1985–2011, the six largest outlet glaciers on the ice cap decelerated by an average rate of − − 21 m a 1 over the 26 year period (0.81 m a 2), or 12% per decade. The change was not monotonic, however, as most glaciers accelerated until the 1990s, then decelerated. A comparison of recent imagery with historical velocity measurements on Highway Glacier, on the southern part of Penny Ice − Cap, shows that this glacier decelerated by 71% between 1953 and 2009–11, from 57 to 17 m a 1.
    [Show full text]
  • Elevation Changes of Ice Caps in the Canadian Arctic Archipelago W
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109, F04007, doi:10.1029/2003JF000045, 2004 Elevation changes of ice caps in the Canadian Arctic Archipelago W. Abdalati,1 W. Krabill,2 E. Frederick,3 S. Manizade,3 C. Martin,3 J. Sonntag,3 R. Swift,3 R. Thomas,3 J. Yungel,3 and R. Koerner4 Received 17 April 2003; revised 19 July 2004; accepted 8 September 2004; published 20 November 2004. [1] Precise repeat airborne laser surveys were conducted over the major ice caps in the Canadian Arctic Archipelago in the spring of 1995 and 2000 in order to measure elevation changes in the region. Our measurements reveal thinning at lower elevations (below 1600 m) on most of the ice caps and glaciers but either very little change or thickening at higher elevations in the ice cap accumulation zones. Recent increases in precipitation in the area can account for the slight thickening where it was observed but not for the thinning at lower elevations. For the northern ice caps on the Queen Elizabeth Islands, thinning was generally <0.5 m yrÀ1, which is consistent with what would be expected from the warm temperature anomalies in the region for the 5 year period between surveys, and appears to be a continuation of a trend that began in the mid-1980s. Farther south, however, on the Barnes and Penny ice caps on Baffin Island, this thinning was much more pronounced at over 1 m yrÀ1 in the lower elevations. Here temperature anomalies were very small, and the thinning at low elevations far exceeds any associated enhanced ablation.
    [Show full text]
  • Changes in Snow, Ice and Permafrost Across Canada
    CHAPTER 5 Changes in Snow, Ice, and Permafrost Across Canada CANADA’S CHANGING CLIMATE REPORT CANADA’S CHANGING CLIMATE REPORT 195 Authors Chris Derksen, Environment and Climate Change Canada David Burgess, Natural Resources Canada Claude Duguay, University of Waterloo Stephen Howell, Environment and Climate Change Canada Lawrence Mudryk, Environment and Climate Change Canada Sharon Smith, Natural Resources Canada Chad Thackeray, University of California at Los Angeles Megan Kirchmeier-Young, Environment and Climate Change Canada Acknowledgements Recommended citation: Derksen, C., Burgess, D., Duguay, C., Howell, S., Mudryk, L., Smith, S., Thackeray, C. and Kirchmeier-Young, M. (2019): Changes in snow, ice, and permafrost across Canada; Chapter 5 in Can- ada’s Changing Climate Report, (ed.) E. Bush and D.S. Lemmen; Govern- ment of Canada, Ottawa, Ontario, p.194–260. CANADA’S CHANGING CLIMATE REPORT 196 Chapter Table Of Contents DEFINITIONS CHAPTER KEY MESSAGES (BY SECTION) SUMMARY 5.1: Introduction 5.2: Snow cover 5.2.1: Observed changes in snow cover 5.2.2: Projected changes in snow cover 5.3: Sea ice 5.3.1: Observed changes in sea ice Box 5.1: The influence of human-induced climate change on extreme low Arctic sea ice extent in 2012 5.3.2: Projected changes in sea ice FAQ 5.1: Where will the last sea ice area be in the Arctic? 5.4: Glaciers and ice caps 5.4.1: Observed changes in glaciers and ice caps 5.4.2: Projected changes in glaciers and ice caps 5.5: Lake and river ice 5.5.1: Observed changes in lake and river ice 5.5.2: Projected changes in lake and river ice 5.6: Permafrost 5.6.1: Observed changes in permafrost 5.6.2: Projected changes in permafrost 5.7: Discussion This chapter presents evidence that snow, ice, and permafrost are changing across Canada because of increasing temperatures and changes in precipitation.
    [Show full text]
  • The Holocene History of Nares Strait Transition from Glacial Bay to Arctic-Atlantic Throughflow
    THE CHANGING ARCTIC OCEAN | SpECIAL ISSUE ON THE IntERNATIONAL POLAR YEAr (2007–2009) THE HOLOCENE HISTORY OF NARES STRAIT Transition from Glacial Bay to Arctic-Atlantic Throughflow BY AnnE E. JEnnINGS, CHRISTINA SHELDON, THOMAS M. CRONIN, PIERRE FRANCUS, JOSEPH StONER, AND JOHN AnDREWS Moderate Resolution Imaging Spectroradiometer (MODIS) image from August 2002 shows the summer thaw around Ellesmere Island, Canada (west), and Northwest Greenland (east). As summer progresses, the snow retreats from the coastlines, exposing the bare, rocky ground, and seasonal sea ice melts in fjords and inlets. Between the two landmasses, Nares Strait joins the Arctic Ocean (north) to Baffin Bay (south). From http://visibleearth.nasa.gov/view_rec.php?id=3975 26 Oceanography | Vol.24, No.3 ABSTRACT. Retreat of glacier ice from Nares Strait and other straits in the Nares Strait and the subsequent evolu- Canadian Arctic Archipelago after the end of the last Ice Age initiated an important tion of Holocene environments. In connection between the Arctic and the North Atlantic Oceans, allowing development August 2003, the scientific party aboard of modern ocean circulation in Baffin Bay and the Labrador Sea. As low-salinity, USCGC Healy collected a sediment nutrient-rich Arctic Water began to enter Baffin Bay, it contributed to the Baffin and core, HLY03-05GC, from Hall Basin, Labrador currents flowing southward. This enhanced freshwater inflow must have northern Nares Strait, as part of a study influenced the sea ice regime and likely is responsible for poor
    [Show full text]